Flexor carpi radialis

What it is

A long muscle running down the front of the forearm from the inner elbow to the base of the index and middle finger metacarpals. Its tendon is prominent at the wrist — it is the one in the middle of the front of your wrist, and the radial artery runs immediately beside it on the thumb side. That relationship is why the pulse is taken where it is.

It arises from the common flexor tendon on the medial epicondyle, shared with several other forearm flexors. That shared origin is the structure implicated in medial elbow pain.

What it does

Flexes the wrist — bends the palm towards the forearm — and deviates it towards the thumb side.

It works with flexor carpi ulnaris, which flexes and deviates the other way; between them the two produce straight flexion, and separately they steer.

What loads it

Wrist curls, gripping, and any movement resisting the wrist being bent backwards. Carrying a load in the hand loads the wrist flexors continuously.

What is commonly got wrong about it

"Golfer's elbow" as a muscle strain. Medial epicondylalgia involves the shared tendon origin rather than the muscle bellies, and current understanding of tendon problems has moved away from inflammation towards changes in tendon structure and load tolerance. Either way it needs a clinician.

That wrist flexion is what grip strength is. Grip is mostly the finger flexors — flexor digitorum superficialis and profundus. The wrist flexors stabilise the wrist so those can work.

That forearm training is one thing. The front and back of the forearm contain a dozen muscles doing distinguishable jobs.